stockard



A ELEG-rma 44 MOTOR p HU-gmum H as sa June 20, 1950 J. M. sTocKARD2,511,832

ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION DRIVE Filed May 27, 1942 2Sheets-Sheet 1 HYDRAULIC Moron 7 8 rllm- MII-mw PRESSURE FLUID INVENToRJOHN M.'STO KARD BY if;

. ATT NEY June 20, 1950 J. M. sTocKARD. 2,511,882

ROTARY PUMP AND MoToR HYDRAULIC TRANSMISSION DRIVE4 Filed May 27, 1942 2sheets-sheet 2 FLUID FIG.2.

PRESSURE FLUID UNLOAD/NG VALVE INTAKE v A Aux/LIARY REL/EF VALVEINVENTOR JOHN M. S TO KARD Patented June 2Q, 1950 "ROTARY PUMP ANDMOTOR-HYDRAULIC TRANSMISSION DRIVE .--John-M.l Stockard, Washington; D;C. Application May 27, 1942, serial-N0. 444,701

(cisco-.53)

.(Granted under the act of March 3, '1883, as

Claims.

This, invention 4relatesto a. 'devicefor ...moving heavy .objectsparticularly l.for .cperatinglwguns turrets... torpedo` launching;gear., heavy tools, or otherl .large machines.

011e object ..of',.the;..device is .to .provide .a

[machine Y,of vthe type which .will` -autorriatically provide :foroperationeithen. bypow'er. or .by hand. Another. object ,of the.invention is toA provide a. hydraulic. j neclianisr'xi.`for...themovement of heavy...objects-,.in in the event .ofapowerfailure, ...ther-.control .elementsaof the mechanism .will .beautomatically. lockedlina positionwhich willpermit. .operation of,theedel/.ice ,byi hand.

A further object of thesdevicefis.tofprovide a mechanism .wherebv .inthe event. of a .power 'fai1ureand, consequently ,operation of the.device ,by ..:hand,. thewpovler. iurnishingdevices will beautomatically., disconnected so... as to eliminate drag.l

Still further. objects, advantages, Aandimprovements will. fbe.,apparent .fromjhe following .description...of. the.. invention. taken.in .connection with. the. accompanying draw-ings, of which:

Fig. .1 ,is aidagtammatic viewshowingthe schematic ,layout of. the:apparatus', .with .sectional views of` the :.operatingvalve mechanism.

Fig. 2 is.a.deta1ed.sec.tiona1,viewof. the. control locking mechanism'and .the .clutch during .the condtons,..ofnormal powenoperation.

Fig. .3..shoivs-,the .same ,apparatus as in- Fig.; 2 but .inpositionfor. hand operation., after, failure of. power. I

. Fig. f4 ..is..a,. crossesectionalpniew .of .tl'ie.. main relieff and.make-.up i-valve. casing. which heads. the variabledischarge pumpiInFig... 1.

-Referringnowto Fig.. 1 V,of the drawings.there isshowma variable,dischargeipumpf A,idriven by an: electric maten-M, or .by anyAother.,suitable sourcesofpower. ...The output. from. the variabledischargapump: is-used .to l.drivel agpositive^..ds placement. hydraulicfmotorf. B` throughisuitahle conduits 4 and.. 5in,a manner. Wellknownin. the art. .The pump. and :hydraulicmotorionthetvpe knownIas.=-.a @Waterbury gear. :may-be .used ,for this purpose. The outputshaft S isadrivenhy the. motor ,B.. through. theclutch. 'Landi the gears8 andi). y

While-the mo.tor.,M..,may .operateeat substantially .constants speed,the.. ,discharge.,4 from .the pi11irip-J-l.may be zvaried to provide an.infinite variationn from. zerodischarge to;.maximum,fiow in eitheridirectionhvuneans of.. acontrolllever ll which operatesa.suitable.ffcamtarraneement or' in the l, case .ofsthencqnilentorialWaterbury gear, a tilting plate. ""The position Of 'this COD- `axnendedApril 3 0, 1928; 370 0. G. 757) trol is` regulatedA by ,.thehandiwheelI2,.which turns. the.- socket, shaft. I 3` through suitable gearsandshafting. The,interior of'. socket shaft I3 is,splined .soasto..impart rotation to, .and allow for. lateral. movement. of .shaft I4.which is .also splined atV I0.

Y Shaft Mis provided .With.threads20v ofrelatively high pitch at the'endopposite that which -is splined. `Gear.15.. is provided..vvith..internalthreads lwhich.. cooperate .With `threads 2l) on shaft I4 so rthatrotarymovementof ,this gear results `in lengthwise. movement. ofthe.shaft .I 4. ,Gear I5v` is. journaledhsoias toA mesh .with idler gear..and. rotates with this idler Which-.is in .turn loperated. by, gear. ,9.

A yoke. IB ,(see',Eg.,.2) vfslides. in..a xed tube I ,'I,..and,.is`pesitionedwithin. this Vtube by a suitable. .guideway to.-pr.eventrotational. movement. Yoke I6,isrconnectedtoshaft.I4..by. a two waythrust bearing'. I8, and. to .theN til-ting .plate controlllbvmeans.ofgthemonnecting link 19.

An auxiliary pump.v 2| .(Fig. 1) ,.driven by motor M, `.takes .oilfroma,suitable source. such asa common `supplytank containing allof thehydraulic elements.and..deliversit.primarily to the main hydraulic.system, that is,. pump. A,. motor B and lines 4.and15 .bvnwayfof supply.line .3S to the make-flip Valve ,in a casing 15 .(Fig. 4). The

` position ofthe..make..up valve, is ,controlledhy means .of appropriateA.ports-and.passages from themain hydraulic. lines 4 and 5,\.so.that oili central section byshort. Shanks. yThis valve is normally .maintainedin a .central...position vby means of the springs 24. The lines land 5conneet the hydraulic. pump A and-.motor B as previously indicatedi ,andin actual. .practice Icy-.pass the voil through. .the valve components,in gcasing ,15 as determined by the. pressure conditions. in thesystem. Referring to the internal organization of. the casing 15,thechannel` 25 leads to the main relief valve. between the .r centralsection. 22.and.the.reduced endsection23. An-

Qther channel`26 leads t0 the valve from line 4.

3 This channel is normally closed off by the central section of thevalve 22. Channel 21 leads from line 5, the other conduit in thehydraulic system connecting pump A and motor B, to the end of the reliefvalve opposite to that of channel 25, between the central section 22 andthe reduced end section 23a. Channel 28 leads from the line 5 to thevalve also, but is normally closed off by the central section 22.Because the area of the central section 22 is larger than that of theend sections 23 and 23a, the tendency of the liquid in each of thechannels 25 and 21 is to f force the valve in the direction of thelarger face, and therefore the valve would move in the f direction awayfrom the channel which is under the greater pressure but for the springs24. However, if the pressure in line 4 and channel 25 becomes excessivefor any cause, such as jamming of the motor B, it will overcome theforce exerted by the oil in channel 21 Iand the spring pressing againstthe end section 23a so that the valve will move far enough to the leftfor oil in channel 25 to be by-passed through channel 28 to line 5,until the pressures in the two lines 4 and 5 are equalzed. Similarly, ifpressure rises excessively in supply pipe 5, for any cause, it will beby-passed through channels 21 and 26 to pipe 4 until the pressures inthe two lines 4 and 5 are equalzed. .v

Still referring to the internal organization of the casing 15, themake-up valve comprises two cylindrical sections or pistons, 29 and 3|of the same cross sectional area, connected by a shank 34 of reducedcross section. This shank extends beyond the ends of the valvesections29 and 3| at each end to limit the lateral movement of the Valve, theareas of the outermost faces of the pistons 29, 3| being equal. Channel32 leads from line 4 through channel 25 to the piston 29 of the make-upvalve, while channel 33 leads from line 5 to the piston 3| of themake-up valve. The differences in pressure in these channels andconsequently on the outer faces of the pistons 29, 3| determine theposition of the valve element. Each of the ports connecting the pistons29 and 3| with the channels 32 and 33 respectively provides a splitpassageway so that oil may reach both faces of a valve piston when it isin a position exemplified by that of piston 29 in the drawing. Inaddition, a space is provided around the shank 34 so that oil may flowto either port 32a or 33av by way of the channel 35 from supply line 36.When the valve is in the position shown in the drawing, oil will ow fromline 36 to channel 32, through port 32a past shank 34 thence to line 4,while piston 3| has cut off the flow of oil from line 36 to channel 33through port 33a and thence to line 5. l

The auxiliary pump 2|, which operates whenever the motor M is inservice, and therefore will cease to operate if there'is a failure ofpower supplied to the motor, also furnishes oil under pressure to asupply line 31. ,4 An auxiliary relief valve 38 (which is no partl oftheinvention) is provided in this line, and discharges through port 38aback into the supply tank in the event of an overload. An unloadingvalve is also provided in this line to permit oil to rdrain from theline to the supply tank in the event of power failure. This valvecomprises two cylindrical sections 39 and 4|, of equal cross sectionalarea, joined by a shank of narrower cross section. A spring 42 urges thevalve in one direction, while the spindle extends beyond the end of thesection 4| to provide a limit for the lateral movementrof the valve. TheQl entering from line 31 follows two paths through channels 43 and 44.Oil in channel 43 is always in contact with the face 4 lb of section 4|.In the position shown in Fig. 1, the pressure against this face is notsufficient to overcome the nominal pressure of spring 42 and the iiow ofoil through channel 44 is therefore cut off by the valve section 39.However, when pump 2| is operating, the oil in channel 43 will push theentire valve Vto the right, uncovering the channel 44, while at the sametime closing the discharge port 45. Oil then ows from channel 44 throughthe space surrounding the shank to the port 46 which leads to the supplyline 41. When the pressure in line 31 and channel 43 drops because ofthe stopping of the -auxiliary pump 2| or any other reason, spring 42will move the valve to the left, cutting olf channel 44 and reopeningport 45, so that oil will drain from the line 41 and discharge from thisport into the supply tank through the channel surrounding the valveshank.

The supply line 41 leads to the automatic control locking mechanism andto the automatic clutch 1. These devices are shown in detail in Figs. 2and 3. The control locking mechanism comprises a detent 48 which engagesan opening 48a drilled in the yoke |6. This detent is provided with apiston 49 which operates in a cylinder 5|, mounted on the side of thetube I1, in response to pressure supplied by oil from pipe 41. A spring52 tends to force the detent 48 into engagement with the opening in yoke|6 at all times, but so long as there is sufficient oil pressure actingagainst the piston 49 it will be held out of engagement as shown in Fig.2.

Clutch 1, as shown in detail in Figs. 2 and 3, comprises a shaft 53 andclutch housing 54 attached to the hydraulic motor B, and driven shaft 55to which is fixed the gear 8. These two shafts are mechanicallyconnected together or discon# nected by means of the clutchplates 56,alternate plates being attached by means of splines to shaft 55 andhousing 54 in the usual manner. The interior of the housing 54 forms acylinder within which a piston 51 ts. This piston is continuously urgedin one direction (as shown in Fig. 3) by the springs 58. Movement inthis direction removes any pressure against Ithe collar 59, which inturn relieves the clutch plates 56 and prevents transfer of rotationalmovement of shaft 55 to shaft 53 or vice versa. A circular channel 6|surrounds shaft 53 and connects with the oil supply line 41. Shaft 53 isdrilled longitudinally from one end to a point opposite the channel 6|,at which point the shaft is provided with additional holes to allow oilto flow from the channel to the longitudinal hole 62. By means of theseoil supply channels, itis possible to supply oil under pressure frompipe 41 to the face of the piston 51 opposite to that against which thesprings 58 press. It will thus be seen that if sufficient pressure issupplied (which will be the case under all conditions of operation whenpower is furnished by motor M) the clutch will be in engagement so thatthe hydraulic motor will drive shaft 55 as shown in Fig. 2.

When it is desired to set the device in operation, the motor M isstarted, which will start the pump A, and the auxiliary pump 2 Undernormal circumstances, oil supplied by the pump 2| will unlock the detent48 which disengages the control for pump A, and will put the clutch 1into engagement, both as previously explained.

Assuming `that the control lever was in a neutral position when thedevice was put in 2:51 `ileso connecting i: pump .A Asand .3 hydrauliczmo tor; B. But ifft' isrdesiredrto 'Shiftfthelfpositioniofrtheoperating .-shaft;v in responsef; to fthe 'wisheszzof .the` operator;Ait onlyrnecessaryi'to.: turn i'the handwheel 1I 2 in l .the :directiondesired finasmuch fas; ther outputashaft' 6;. Vis usuallylattached to armechanism fi-possessing l Vgreat :inertiay this shaftewill notvrotateunless a: substantialfforce istappliedsto it. @At :any rate,:theinertiaz'offthe load 1in all; cases-` willrfbeisuiiicienn lso*I fthatlfrotation.ofgthegzhandwheel' I 2 Yrandy-.consequent irotation -ofthe;1shaft==.| 4, rWillinot immediately result in rotationof v,the gear?llrbutfrather inca lateral displacementrof the'slflaftt =I 4zduectofthe. pitchaof .the threads f 12 U. 'f'lhiswflateral y;displacements will operate z the; control lever :1I I so that: the .pumpA =Wi1lf begin-ltorsupply;oilzunderepressure to the motor :'B, whichnin: turn.'Willioperate'` gear 8'; and the shait'zthrough gear 9. Theresultantlmovement lof shaft-:45,ra'nd` gear 9-fWi1lfturn AgearIthroughaidler 30. The precedingoperationsisfare designed so that therotation of gear Iithus instituted Willfbe-:sucl'r asl ltoY return ytheshaftf I4, and; thefcontrolclever I I to itszroriginal ipostion,atfwhich time thezcontrol: lever Willbegfinneutral and `fthe.f-eirculationf1of: oil-to. thewmotor Bvwill stop. In effect; this@portion offthe-deviceisv-a Sffollow-g-u-p mechanism: offsimplefconstruction.

lIn the event ofa powenfailureiand the consequent.` stopping fof ther-motor M, f there-rwill; 7no longerbefafsupply otaoil-fto, operatcsthehydraulic motor B- fandfthe shaft 5.6. -If no-A means "were provided or:disconnecting the imotor "from the. shaft 6 fit would beextremelyndifcultre for hand opera-tion ofx the: device' toreffectmovement ofl shaft 6, pand-. in. cold :Weather- :it might ibe:impossible. Butyvhenmotor M: ceases operating, the :pump 2 I:will-alsofstop, thusidisengagingwthe clutch 'I and disconnectingithemotor; B :from the loaden-shaft 6. Stopping ofgtheppumpl will valsorelease the detent 48 and -rpermit .:it to `be urged intoengagementIwith thesholef48a inhyoke ltbyfthe.spring-i512 :Ifswhen thepowerfailed, lever l I wasf inother than the Vneutralpositionthe :detent.48k-will nottherrengagepbut by rotation' `of shaftI I 4 "nthe proper`:direction the-lever can-be-returned toffneutrale andfthe detent willthen@ engage -theholednffthesyokel16. Oncethe detent has goneintoengagementnwith the` yoke Y, I6,-.latera1 .movement .or the; shaft t I4Willh be prevented until lpower is again suppl-led to .pump 2 I and .lthe .detent thus t .forced :back out of. engagement. il Once lateraldisplacement of shaftl4 has.ibeen stopped,a furtherrctation of. thehandwheel l2.. andthe shaft wI 4. .can yonly result in movement of theshaft. Gmhroughgear I5, idler 30.,.and gearwinasrnuchas, gear L5 isincapable `of lateral movernent itself. Operation of 4the shaft 6 is,facilitated. aspreviously explained bythe disengagement of the motor B.'When power is subsequently restored to motor M 'thewhole system willreturn topower operation automatically.

Whilepthe invention, has been described Withreference to certainpreferred examples thereof which givesatisfactoryresults, it will beunderstood by those skilled in the art to which the invention pertains,after understandingthepinvention, that various changes and'modilcationsmaybe made Without departing from; the vspirit andscope of theinvention, and it is-rnyintention, therefore,l to cover ini the appendedclaimsv all such `changes `and .modications fThe invention Ahereindescribed may: bev manu- 6 facturedaandcusedsbya omforithe GoyernmentcoftheaUnited l'states:ofi-Americanfongovernmental purposeszwvthoutsthe,epaymentpfiaany royalties thereonzorirtherefcr. XrWhatf. isclaimedcaszgnew and desired to bessecuredcbyL'Letters:Patentrof the.;United Statessis:

l; Mopen/lent.gimparting-sappa1atus,f ycomprisingsa;fprimeffmover;tarmaimpump .operated-by saidaprirnemoyen-.aan auxiliarycpumnfoperatcd by saidwzprime"rmoyerpfa fluidv4operatedsmotor operated ibyisaidmainizlmmpp adriven-` shaft; :andmeans includingrsaidf auxiliary s pump`tcm-fautomaticazllyelengagingfsaid@ tdriven{shaft-{With-saiduidxeperatcd motor ravhen said; gprimeffmoven operated.

2;) Movement f imparting i apparatus, comprisingc a prime cmover,..a\.fmainapumpqoperatede by saidcprimeamover,ganfauxiliaryypump operated bysaid- 1 prime mover, a" 'fuid l: operated I'motor operated yfloy;v :saidmain lpump, y :av driven -;shaft, means: includingsaid auxiliary` :pumpfor Tautomatically engaging; -said i driven shaft ,with saidfluid'yoperatedemotor fwhen 1saidf-prime imoverc is operated; andmeans.v for lautomatically .disengaging, saidlsha-ft iromsaidffluidoperated :motor whenlsaidg-primel fmover; :isf inoperative.

l 3.-; llpparatus` f Ifor nim-parting movement ,5to @a Shaft comprisingf ai :prime: mover, .a :main Ypuginp operated i Eby said lprime f;mover,:an auxiliary purnparoperated v-byf-sa-id prime .zmover, t a fluidoperatedmmotor coperatedffbyesaid fmain yfpump, a clutchwior7'operablyffengagling said` shaft :with said fluid operatedinotorpandwmeansl including saidianxiliary :pumporcautom'atically;,engaging said;r clutchcyl/hen.=` :said :prime-1zmovercis operated.

e Il, @Apparatus for :imparting movement; to a shatcomprising a primemover, a vmainuid pump operated :@-by vsaid i prime mover, a fluidopeizatedg-motor :Operated bye saidtmain pump, means including 4.- a.clutchtffor operatively y,engagingsad shaitlwith said-iluid operatedmotor, an auxiliarylfpumproperated bysaidprime Lmoveradaptedftoamaintain said` clutchiina engagement Whenrsaid; prime; .moyenactuates. said auxiliary pumprmanuallyeactuated means capable .ofdrivngtsaid; shaft, ii-ndependently; pofaid-nuid v,operated-.motor,.land means ...-forr. automatically. ,disengagingaid.clutchviwhenfsaid prime -.mover .is inoperative, whereby saidshait isfreed from the ,drag .ofsaid fluid ,operated motor when said shaftisdnivenbyfsaid.manually actuated means. i 5.. Apparatus. ,fon,impartingmotion to a. shaft. comprising-. aprirne moyen 'ai .fluidpumproperated,by .said.; prime ,moverfa fluid operated motor operated, .byMsaid, mump, means forperativdy engaging said shaft ,Withaid fluidoperated motor, means. for regulatingfthe iiuiddischarge from^said..p11mp,..1nanual control means. operatively connecting with .said.iluid discharge regulatingimeans.,,means .operatively connecting said"shaft with, sadinanual, control means and luidoperated. means,operative to insure manual actuation 4ot .said Shaft'. by said manualcontro] means Whensaid prime. moveri is inoperatiije.

l 6.- Apparatus ier imparting motiontoi a shaft, comprisinga primemovenafluid pump operated by sad, prime mover, Vafluid yoperated motoroperated by said pur- 1.10, 'ud .operated :means actuated nby said .prirne .moyer j for `ope ratively engaging said shaft with said uldoperated motor, means for regulating the Jliuid"discharge from saidpump; manuall control means operatively connecting-With saidj'iluiddischarge'regulatingfmeansrrneans 'operatively connectingJsa'ld'shaft--with f manuallcontrol means,-J and means 4v7 for. disengagingsaid'shaft from said motor when saidprime mover'is inoperative, wherebysaid shaft is disengaged from said uid motor for actuation by said`manual control means when said prime mover is inoperative.

7. Movement imparting apparatus comprising a prime mover, a main pumpoperated by said prime mover, a fluid operated motor operated by saidmain pump, a driven shaft, said shaft being connected with said fluidoperated motor by Aa. clutch mechanism, an auxiliary pump operatedconcurrently with said main pump, said clutch mechanism being maintainedin engagement by fluid supplied under pressure by said auxiliary pump.8. Apparatus' for imparting movement to a shaft, comprising a primemover, a main pump operated by said prime mover, a fluid operated motoroperated bysaid main pump, a clutch for operatively connecting saidshaft with said motor, anauxiliary pump operated concurrently with saidmain pump |by said prime mover for Aengaging said clutch when said primemover is operative, means for regulating the fluid discharge from saidmain pump, manual control means operatively connected with saiddischarge regulating means, means voperatively connecting said shaftwith said manual control means, and means for ydisengaging said clutchwhen said prime mover isinoperative, whereby said shaft is disengagedfrom said fluid motor for actuation by said manual control means whensaid prime mover is inoperative.

9. Apparatus for moving heavy objects comprising a prime mover, a mainpump operated by said prime mover, a fluid operated motor operated bysaid main pump, a driven shaft, said shaft being operatively connectedto said fluid operated motor, an auxiliary pump operated concurrentlywith said main pump, means for regulating the discharge from said mainpump, manual control means operatively connected with said dischargeregulating means, a motion translating system operatively connectingsaid driven shaft and said manual control means, and locking means forpermitting operation of said driven shaft by said manual control meansindependently of said discharge regulating means, said locking meansbeing maintained in inoperative position by fluid controlled by saidauxiliary pump.

`10. Apparatus for moving heavy objects comprising a prime mover, a pumpoperated by said prime mover, a fluid operated motor operated by saidpump, a driven shaft, said shaft being operatively connected to saidfluid operated motor, means for regulating the discharge from said pump,manual control means operatively connected with said dischargeregulating means, a motion translating system operatively connectingsaid driven shaft and said manual control means, locking means forpermitting operation of said driven shaft by said manual controlindependently of said discharge regulating means, and means including anauxiliary pump operated concurrently with said main pump for supplyingfluid under pressure to said locking means for maintaining the latter inunlocking position, said locking means becoming operative automaticallyupon the failure of said auxiliary pump to supply fluid to said lockingmeans.

11. Apparatus for moving heavy objects comprising'a prime mover, a mainfluid pump operated by said prime mover, a fluid operated motor operatedlby said main pump,l a driven y. "shaft, said shaft being @connected to-sad uid operated motor by a clutch mechanism, an auxiliary fluid'pumpoperated concurrently with said main pump, means for regulating thedischarge from said main pump, manual lcontrol means operativelyconnected with said discharge regulating means, a motion translatingsystem op- 'erativelyconnecting said driven shaft and said manualcontrol means, and locking means for permitting operation of said drivenshaft by said manual control independently of said'discharge regulatingmeans, said clutch mechanism being maintained in engagement 'and saidlocking means being maintained in inoperative position by fluid suppliedby said auxiliary pump.

12. Apparatus for imparting movement -to a shaft, comprising a primemover, a pump operated by said .prime mover, a fluid operated motoroperated by said pump, and fluid operated means driven by said primemover for automatically engaging said shaft with said uid operated motorwhen said prime mover is operative.

13. Apparatus for imparting movement to a shaft, comprising a primemover, a fluid pump operated by said prime mover, a ud operated motoroperated by said pump, a clutch for operatively connecting said shaftwith said motor, fluid operated means actuated by said prime mover formaintaining said clutch in engaged condition when said prime mover isoperative, manually actuated means for driving said shaft independentlyof said iiuid operated motor, and means for automatically disengagingsaid clutch when said prime mover is inoperative, whereby said shaft isdisengaged from said uid motor for actuation by said manually actuatedmeans when said prime mover is inoperative.

14. Movement imparting apparatus comprising an output shaft connectiblewith a heavy load, a mechanical power source for moving the outputshaft, comprising a serially connected prime mover, main pump having afluid discharge regulating means and hydraulic motor having a clutchresponsive to fluid pressure to assume an lengaging position, a detentfor the regulating means responsive to fluid pressure to assume anunlocking position, an auxiliary pump driven by said prime mover,supplying pressure iiuid to the clutch and detent for the respectivepurposes, a manual power source also for moving the output shaft, and afollow-up mechanism constituting a coupling between the manual powersource, the uid discharge regulating means, the clutch and the outputshaft, for neutralizing said regulating means after each manualoperation of the manual power source.

15. Movement imparting apparatus comprising an output shaft connectiblewith a heavy load, a mechanical power source for moving the outputshaft, comprising a serially connected prime mover, main pump having afluid discharge regulating means and hydraulic motor having a clutchresponsive to uid pressure to assume an engaging position, a detent forthe regulating means responsive to uid pressure to assume an unlockingposition, an auxiliary pump driven by said prime mover,'supplyingpressure uid to the clutch and detent for the respective.

purposes, a manual power source also for moving the output shaft, and afollow-up mechanism consisting of a telescopic screw shaft between themanual means and the iiuid discharge regulating means, and a gear trainconnected with 9 the output shaft and having terminal gears re- Numberspectively carried by the clutch and screw shaft. 2,097,857 JOHN M.STOCKARD. 2,298,649

REFERENCES CITED 5 The following references are of record in the Numberme of this patent: UNITED STATES PATENTS 9 Number Name Date 10 567,327Volker Sept. 8, 1896 10 Name Date Ferris Nov. 2, 1937 Russell Oct. 13,1942 FOREIGN PATENTS Country Date Great'. Britain Jan. 14, 1911 GreatBritain Feb. 14, 1914

